On November 16, Biogen announced that Vumerity (diroximel fumarate) was granted marketing authorisation by the European Commission for the treatment of adults with relapsing-remitting multiple sclerosis (RRMS). The approval is based on data from pharmacokinetic bridging studies comparing Vumerity and Biogen’s Tecfidera (dimethyl fumarate), an older generation oral fumarate treatment with well-established, long-term efficacy and safety. Having demonstrated a more favourable gastrointestinal (GI) tolerability and comparable efficacy to that of Tecfidera, Vumerity is expected to claim market share both from new RRMS patients starting on an oral fumarate treatment and those switching from Tecfidera due to GI side effects. This approval comes just in time to help Biogen offset anticipated sales erosion in the multiple sclerosis (MS) space, as the company’s blockbuster drug Tecfidera approaches loss of patent protection in the European markets by 2024.

Vumerity is an orally administered, second-generation fumarate that rapidly converts to monomethyl fumarate in the body, similar to its predecessor, Tecfidera. Vumerity was approved in the US in October 2019 based on positive data from the Phase III EVOLVE-MS-2 (NCT03093324) study, which evaluated the GI tolerability of Vumerity compared to Tecfidera in patients with RRMS. The results showed that patients on Vumerity had a lower rate of overall treatment discontinuation compared to those on Tecfidera (1.6% versus 6.0%, respectively). Furthermore, the difference in the discontinuation rates specifically due to GI tolerability were 0.8% for Vumerity compared to 4.8% for Tecfidera.

Recently, several cost-effective generic versions of Tecfidera became available in the US market following the drug’s patent expiry in 2020. Some key opinion leaders interviewed by GlobalData stated that although Vumerity has overtaken Tecfidera since its launch in the US, particularly in new RRMS patients, Vumerity has struggled to contend with the heavy competition from generic oral fumarates. In the US, generics currently represent the highest share of prescriptions within this therapeutic class, as most MS patients do not find the GI side effects of dimethyl fumarate to be a major issue.

In Europe, Biogen is likely aiming to expand its existing share in the fumarate class, thus mitigating the imminent risk of Tecfidera generic infiltration before 2024. In line with its current pricing strategy in the US, GlobalData anticipates Vumerity will have a much lower price tag than Tecfidera in the European markets. This will make it a more enticing option upon launching in those markets.

However, given the limited advantages of Vumerity over dimethyl fumarate, as well as the heavy competition among the oral MS therapies, it will most likely be difficult for the drug to replicate the impressive growth trajectory of Tecfidera, which had peak global sales of $4.4bn in 2019. GlobalData expects Vumerity to have moderate yet significant uptake globally, likely reaching blockbuster status by 2027.